Mobile malware that affects Symbian Series 60 handsets is being used to create a botnet.

Security firm NetQin claims as many as 100,000 smartphones have been compromised with the malware, which typically poses as a game and affects Series 3 and % Symbian devices. NetQin said the malware is programmed to send SMS messages from compromised devices.

"These botnets do one of two things; send messages to all the contacts of the address book directly, or send messages to the random phone numbers by connecting to a server,” NetQin explains in a blog posting: http://blog.netqin.com/en/?p=168

“The viruses will delete the sent messages from the user’s Outbox and SMS log. All messages contain URLs linked to malicious sites that users won’t be able to see until after they’ve fallen into the virus trap.”

The Symbian Foundation said that the certificate used to sign has been revoked, so providing revocation checking is enabled on a phone the malware will not run. Symbian downplayed the threat of the malware which a spokesman described as posing only a "very minor threat".